You sound like a Scottish nationalist. They're also fond of claiming that the reasons why they lost their referendum no longer apply.
Nobody voted for a coalition in 2010. All the parties made a pitch for outright control of the Commons and I doubt many people who voted Lib Dem, Tory or Labour, did so in order to influence the structure and nuances of the resulting government, but rather to state which party should have the job, or else (in the case of the Lib Dems) to make a principled but futile stand against the rest.
I'm not sure which polls you're reading to suggest people may deliberately choose a coalition this year by opting to support minor parties. British electoral arithmetic is well understood. There can't be many people who actually think about their vote, who don't understand the likely consequences of voting for a party that has a thin sheen of support across a nation of 65 million people, but almost no depth of support in any one place.